1. Field of the Invention
The present invention relates to an enclosure for a piece of electronic equipment including a printed circuit board (hereinafter called a PCB), and more particularly to an improved enclosure that both reduces the number of components making up the enclosure and simplifies its assembly.
2. Description of the Related Art
In the past, there has been a desire to reduce the number of components of and improve the efficiency of assembling a piece of electronic equipment that includes a PCB, and in particular, diecast frames and chassis with various structures have been proposed to that end (for example, as disclosed in Japanese Unexamined Patent Application publications H11-1-3177 and H7-85645).
For example, FIG. 8 and FIG. 9 show an enclosure structure that is applied in radio equipment, these drawings respectively being an outer perspective view thereof and an exploded perspective view of the constituent components thereof.
In these drawings, the reference numeral 101 denotes a diecast chassis, 102 is a PCB, 103 is an upper cover, 104 is a lower cover 105 are operating electronic components such as potentiometers, rotary encoders, and variable capacitors, 106 is a liquid-crystal display panel (hereinafter called an LCD panel), 107 is a panel circuit board, 108 is a front panel, 109 are knobs, and 110 is an acrylic sheet. The enclosure of the radio apparatus 100 is assembled by the following procedure.
First, the PCB 102 is mounted to the diecast chassis 101, this being done after a connector 102a is mounted to the PCB 102.
The panel circuit board 107 also constitutes a PCB, to which each of the operating electronic components 105 is soldered and fixed, with these electronic components passing through holes formed therein. The terminals of the operating electronic components 105 are soldered to conductive pattern parts of the panel circuit board 107, and the LCD panel 106 panel is mounted to a window formed in the panel circuit board 107.
Additionally, a cable 107a with a connector is connected to the panel circuit board 107, thereby completing the overall panel circuit board assembly 107b. 
Next, there are holes and a window formed in the front panel 108 at positions corresponding to the holes and window of the panel circuit board 107, and the panel circuit board assembly 107b, to which are mounted the components 105, 106, and 107a, is mounted to the rear surface of the front panel 108, the transparent acrylic sheet 110 being mounted to the window part formed in the front surface of the front panel 108.
Then the overall front panel 108, to which is mounted the panel circuit board assembly 107b, is mounted to the front side of the diecast chassis 101, after which the cable 107a with a connector of the panel circuit board assembly 107b is connected to the connector 102a on the PCB 102 side, and if there is a connector or the like mounted to the rear surface of the diecast chassis 101, this is also connected to the PCB 102.
After the above, the upper cover 102 and the lower cover 104 are mounted to the diecast chassis 101, and finally knobs 109 are pressed onto shafts that pass through the holes in the front panel 108 and which serve as operating parts, thereby completing the radio apparatus 100 as a product.
Recently a bracket or the like for mounting discrete components has come to be fixed to the PCB 102, the components 105 being directly mounted to the PCB 102 along with an electronic circuit, so as to form an assembly, thereby simplifying the assembly procedure.
When using a diecast chassis 101 such as described with regard to the related art example, because the diecast chassis serves as a base frame that forms the enclosure, the upper and lower covers 103 and 104 and the front panel 108 become essential members of the enclosure.
Therefore, there is not only an increase in the number of components, but also an increase in the number of screw tightening locations, this leading to an inevitable increase in the work of assembling the enclosure. When a panel circuit board 107 is used, because discrete components 105, 106, and 107b are also mounted at the same time, management of components at the assembly stage becomes extremely troublesome.
Additionally, because the diecast chassis 101, the upper and lower covers 103 and 104, and the front panel 108 are each fabricated at separate diecast and sheet metal process steps, the procurement scheduling for these components also becomes troublesome.
Accordingly, it is an object of the present invention to provide a chassisless enclosure structure with an outer enclosure having a split construction, thereby providing rational solutions for the above-noted problems
The present invention is an enclosure structure for electronic equipment having an internal PCB, this structure being formed by:
a PCB having mounted to it a plurality of electronic components operable from outside, the operating parts of these electronic components being disposed on one and the same plane and extending outside the PCB; and
an outer enclosure formed of a pair of diecast housings, each integrally formed by a frame-shaped side wall part and a planar part so as to enable the housing of the PCB, by joining edges of the frame-shaped side walls of each housing together;
wherein the PCB is mounted in one housing of the outer enclosure so that a plane in which the operating parts are disposed substantially coincides with an edge of the frame-shaped side wall, and cutouts are formed in edges of the housings so that, when the PCB is mounted, holes are formed in regions of the outer enclosure corresponding to the operating parts of the electronic components of the PCB.
In the enclosure structure of the present invention, a PCB is installed in the well of an outer enclosure made of a pair of diecast housings that are joined together.
A plurality of electronic components that are operated from the outside are mounted on the PCB, the operating parts of these components being disposed on one and the same plane.
Therefore, it is possible to have the joining surface of each of the housings of the outer enclosure coincide with the plane on which the operating parts of electronic components of the PCB are disposed.
If cutouts are formed in the joining plane of the housings (edges of the side wall on the frame side), taking into consideration the positions of the operating parts with the PCB mounted to one of the housings so as to be installed within the outer enclosure, holes are formed in the side wall of the outer enclosure in regions that corresponds to the positions of the operating parts, enabling the mounting of knobs onto the operating parts from outside the outer enclosure.
According to the present invention, by merely joining a pair of divided housings that form an enclosure, it is possible to achieve a chassisless structure for directly mounting a PCB to one of the housings, so that in the assembly step it is only necessary to mount the PCB to the housing and tighten the screws that join the housings.
An enclosure for electronic equipment generally has externally mounted connectors and an LCD panel. In the present invention, if these items are disposed on the same plane onto which the operating parts of the electronic components are disposed, and cutouts are formed so as to form a corresponding region of the housings to serve as holes of appropriate sizes and windows, the same method can be used to install connectors and an LCD panel to the side wall of the outer enclosure.
Additionally, because the outer enclosure is formed by a pair of housings that are split into top and bottom parts, it is possible to simplify the method of mounting the transparent sheet provided at the front surface of the LCD panel.
More specifically, a slit into which the side edge of a transparent sheet is inserted is formed in both inside surfaces of the half-frame cutout formed so as to provided a window in a region corresponding to the LCD. When the end surfaces of each housing frame side wall part are joined, this transparent sheet is inserted into the slit and the outer enclosure is assembled, thereby enabling the mounting of the transparent sheet without the need for troublesome procedures such as screw tightening or the used of an adhesive.
In manufacturing a housing by diecasting, flashing often occurs at the corner part of edge of the frame-shaped side wall.
Because the edges of the frame-shaped side walls served as the joining surfaces between the housings, this flashing can hinder the achievement of a proper joining, and can also result in dangerously sharp protrusions on the outside of the outer enclosure, making it necessary to remove such flashing.
Therefore, it is necessary to provide a separate deflashing step with respect to the housings that are obtained in the diecast step, this resulting in an increase in the manufacturing cost.
This problem can be solved by inserting a soft, belt-shaped member having an H or T cross-sectional shape between the edges of the frame-shaped side walls of the housings when joining the edges of the housings, so that the corner parts of this member minimally cover the corner part formed between the edges and the outer side wall surfaces.
According to the enclosure structure of the present invention, because the thermal capacity of the diecast housing is large and the overall outer enclosure is exposed to the outside at all times, this structure is ideal for radiating heat.
Therefore, if an electronic component that generates a large amount of heat is mounted in contact with an inner surface of one or both of the housings, it is possible to achieve highly efficient radiation of heat. If heat-radiating fins are additionally formed integrally with the diecast housing, on the outer surface thereof, it is possible to achieve a further improvement in heat radiating effectiveness.